I think the “time is money” metaphor is very useful to thinking about time as a limited resource. The average person has about 630,000 hours in their life. Take out 210,000 for sleeping, a largely involuntary time sink. The time cost is truly the more expensive portion. This limited resource consideration is even more important to consider there are strict upper-limits to how much time someone will have, and no one has lived 1,000,000 hours.